It is already known to provide a cine camera either with a shutter open angle varying device where the rotary shutter is constructed from a plurality of shutter blades to obtain an arbitrary shutter open angle, or with a shutter open angle varying device where the shutter open angle is discretely changed over, for example, to 150.degree., 216.degree. or the like. However, these conventional cine cameras are unable sometimes to attain a desired shutter open angle even though the operator believes he has set the shutter open angle variation setting means to the desired angle, because a manufacturing error between the shutter open angle varing device and the shutter open angle variation setting device exists. Further the desired shutter open angle is not always able to be obtained due to the back lash existing between the various mechanical components. The shutter open angle varying device in the conventional cine camera also employs a so-called "open loop" control system where there is provided no means of detecting the afore-said error and of compensating that error, so that the influence of this photographic error on photography becomes serious particularly when an object to be photographed, for example, a television picture, necessitates an accurate exposure time. In other words, in taking photographs of television pictures whose vertical synchronizing signal is 60 Hz and horizontal synchronizing signal is 15750 Hz, as the interlacing scanning is employed, the exposure time of 1/60.times.2=1/30 second must be accurately obtained for each film frame. Also, if the exposure time of the camera is longer than 1/30 second, the scanning lines in a television picture expose the surface of a frame twice in a portion, and therefore the twice-exposed portion of the film frame leads to over-exposure with the result that stripes are recorded along with the picture image. Conversely, when the exposure time of the camera is shorter than 1/30 second, an under-exposed portion due to the lack of scanning lines results in a black stripe formed within the image. These white stripes and black stripes of the image projection screen give to the viewer an extremely unnatural impression. Therefore, in application of the camera to television picture photography, it is required to control the exposure time of each frame with high accuracy for a constant value of 1/30 second as mentioned above. The determinative factors of exposure time in taking pictures may be expressed as:
(1) The average frame frequency when the film is transported;
(2) The shutter open angle; and
(3) The rate of variation of shutter rotation speed existing in every one frame exposure operation.
Now assuming that the frame frequency is constant at 18 frames/second, then the shutter open angle .theta. necessary to obtain an exposure time of 1/30 second is determined from the equation 1/18.times..theta./360=1/30 to be .theta.=216.degree.. In other words, when the film is transported at a constant frame frequency of 18 frames/second, a television picture can be suitably photographed by adjusting the shutter open angle .theta. to 216.degree..